Truss spacing question

[Alexvbugman]

Hello, I'm not real familiar on Truss specs, but was wondering why FBI buildings is showing their Truss's on 9' centers and DIY buildings is showing them on 4' centers. Same size buildings and same snow load, any insight would be appreciated.

 

[drivesitfar]

Alex: welcome to the forum. can you post any pictures of the tresses? i'm guessing the FBI's tresses might be thicker or have some metal supports??

 

[tomroblee]

I'm guessing that the 9' truss spacing is based on a 9' post spacing. There are some strength advantages to having the trusses attached directly to the posts.

If you ever want to add a ceiling, 4' spacing is the maximum distance you will want.

Trusses engineered for 9' spacing will obviously need to be built with larger dimension lumber than trusses engineered for 4' spacing. Cost wise, there shouldn't be much difference. If you are wanting to add a ceiling, 2' spacing would be even better than 4' spacing, but would increase the price by a noticeable amount.

If you are going to add a ceiling (and/or use the tresses for overhead storage), the trusses need to be engineered for the added load---regardless of the spacing.